Heretofore known are various kinds of fluorescent crayons. Depending on the required quality characteristics, those crayons are manufactured by melt-blending a natural high-melting wax (carnauba wax, rice bran wax, etc.) or a synthetic high-melting wax (an aliphatic amide etc.) with an intermediate-melting wax (hydrogenated oil, paraffin, etc.) and a fluid oil (coconut oil, liquid paraffin, etc.) according to a suitable recipe, adding a fluorescent dye or pigment, casting the resulting composition in a predetermined mould, and cooling it to solidify in situ.
However, the conventional fluorescent crayon has the drawback of poor color development as well as the drawback that bleeding occurs on aging. Moreover, the density of the developed color is low and unless the fluorescent coloring agent is added in a large amount, no bright color can be obtained, while the use of such a large amount of the fluorescent coloring agent would result in deteriorated drawing quality and may cause a decrease in adhesion.
In addition, those fluorescent crayons have the same problems as those of the regular crayons. Thus, they are insufficient in adhesion to non-absorbent surfaces such as metal, glass, and plastic substrates and cannot be applied to drawing on those materials. Another problem is that when one touches those crayons, the crayons are ready to stain the fingers. Moreover, at high temperatures, the fluid oil component of the crayon bleeds out to detract from the stability of quality.